- ID:
- ivo://CDS.VizieR/J/A+A/470/787
- Title:
- High energy peaked BL Lacs optical spectros.
- Short Name:
- J/A+A/470/787
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The multi-frequency sedentary survey is a flux-limited, statistically well-defined sample of highly X-ray dominated (i.e., with a very high X-ray to radio flux ratio) BL Lacertae objects, which includes 150 sources. In this paper, the third of the series, we report the results of a dedicated optical spectroscopy campaign that, together with results from other independent optical follow-up programs, led to the spectroscopic identification of all sources in the sample. We carried out a systematic spectroscopic campaign for the observation of all unidentified objects of the sample using the ESO 3.6m, the KPNO 4m, and the TNG optical telescopes.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/601/A35
- Title:
- High-fidelity VLA imaging of 3C273
- Short Name:
- J/A+A/601/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 3C 273, the nearest bright quasar, comprises a strong nuclear core and a bright, one-sided jet extending ~23 arcseconds to the SW. The source has been the subject of imaging campaigns in all wavebands. Extensive observations of this source have been made with the Very Large Array and other telescopes as part of a campaign to understand the jet emission mechanisms. Partial results from the VLA radio campaign have been published, but to date, the complete set of VLA imaging results has not been made available. We have utilized the VLA to determine the radio structure of 3C273 in Stokes I, Q, and U, over the widest possible frequency and resolution range. The VLA observed the source in all four of its configurations, and with all eight of its frequency bands, spanning 73.8MHz to 43GHz. The data were taken in a pseudo-spectral line mode to minimize the VLA's correlator errors, and were fully calibrated with subsequent self-calibration techniques to maximise image fidelity. Images in Stokes parameters I, Q, and U, spanning a resolution range from 6 arcseconds to 88 milliarcseconds are presented. Spectral index images, showing the evolution of the jet component are shown. Polarimetry demonstrates the direction of the magnetic fields responsible for the emission, and rotation measure maps show the RM to be very small with no discernible trend along or across the jet. This paper presents a small subset of these images to demonstrate the major characteristics of the source emission. A library of all ~500 images has been made available for open, free access by interested parties.
- ID:
- ivo://CDS.VizieR/J/A+A/415/549
- Title:
- High-frequency polarization of Kuehr sources
- Short Name:
- J/A+A/415/549
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed 250 of the 258 southern sources in the complete 5GHz 1Jy sample by Kuehr et al. (1981, Cat. <VIII/5>) using the Australia Telescope Compact Array (ATCA) at 18.5GHz. This paper focuses on the polarization properties of this sample, while other properties will be addressed in a future paper.
- ID:
- ivo://CDS.VizieR/J/other/JApA/25.143
- Title:
- High galactic latitude HI absorption survey
- Short Name:
- J/other/JApA/25.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Giant Meterwave Radio Telescope (GMRT) to measure the Galactic HI 21-cm line absorption towards 102 extragalactic radio continuum sources, located at high (|b|>15{deg}) Galactic latitudes. The Declination coverage of the present survey is DE~-45{deg}. With a mean rms optical depth of ~0.003, this is the most sensitive Galactic HI 21-cm line absorption survey to date. To supplement the absorption data, we have extracted the HI 21-cm line emission profiles towards these 102 lines of sight from the Leiden Dwingeloo Survey of Galactic neutral hydrogen. We have carried out a Gaussian fitting analysis to identify the discrete absorption and emission components in these profiles. In this paper, we present the spectra and the components. A subsequent paper will discuss the interpretation of these results.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/1766
- Title:
- High-redshift AGN feedback in SZ clusters
- Short Name:
- J/MNRAS/471/1766
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of active galactic nucleus (AGN) feedback at higher redshifts (0.3<z<1.2) using Sunyaev-Zel'dovich selected samples of clusters from the South Pole Telescope and Atacama Cosmology Telescope surveys. In contrast to studies of nearby systems, we do not find a separation between cooling flow (CF) clusters and non-CF clusters based on the radio luminosity of the central radio source (cRS). This lack may be due to the increased incidence of galaxy-galaxy mergers at higher redshift that triggers AGN activity. In support of this scenario, we find evidence for evolution in the radio-luminosity function of the cRS, while the lower luminosity sources do not evolve much, the higher luminosity sources show a strong increase in the frequency of their occurrence at higher redshifts. We interpret this evolution as an increase in high-excitation radio galaxies (HERGs) in massive clusters at z>0.6, implying a transition from HERG-mode accretion to lower power low-excitation radio galaxy (LERG)-mode accretion at intermediate redshifts. Additionally, we use local radio-to-jet power scaling relations to estimate feedback power and find that half of the CF systems in our sample probably have enough heating to balance cooling. However, we postulate that the local relations are likely not well suited to predict feedback power in high-luminosity HERGs, as they are derived from samples composed mainly of lower luminosity LERGs.
- ID:
- ivo://CDS.VizieR/J/ApJ/709/424
- Title:
- HII regions identified with WMAPS and GLIMPSE
- Short Name:
- J/ApJ/709/424
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Wilkinson Microwave Anisotropy Probe (WMAP) maximum entropy method foreground emission map combined with previously determined distances to giant HII regions to measure the free-free flux at Earth and the free-free luminosity of the Galaxy. We find a total flux f_{nu}_=54211Jy and a flux from 88 sources of f_{nu}_=36043Jy. The bulk of the sources are at least marginally resolved, with mean radii ~60pc, electron density n_e_~9cm^-3^, and filling factor {Phi}HII~0.005 (over the Galactic gas disk). We use GLIMPSE and Midcourse Space Experiment (MSX) 8um images to show that the bulk of the free-free luminosity is associated with bubbles having radii r~5-100pc, with a mean of ~20pc. These bubbles are leaky, so that ionizing photons emitted inside the bubble escape and excite free-free emission beyond the bubble walls, producing WMAP sources that are larger than the 8um bubbles. We suggest that the WMAP sources are the counterparts of the extended low density HII regions described by Mezger (1978A&A....70..565M). The 18 most luminous WMAP sources emit half the total Galactic ionizing flux.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/1790
- Title:
- HIJASS HI survey in the Ursa Major region
- Short Name:
- J/MNRAS/428/1790
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted the first blind HI survey covering 480deg^2^ and a heliocentric velocity range from 300 to 1900km/s to investigate the HI content of the nearby spiral-rich Ursa Major region and to look for previously uncatalogued gas-rich objects. Here we present the catalogue of HI sources. The HI data were obtained with the four-beam receiver mounted on the 76.2-m Lovell telescope [full width at half-maximum (FWHM) 12-arcmin] at the Jodrell Bank Observatory (UK) as part of the HI Jodrell All Sky Survey (HIJASS). We use the automated source finder DUCHAMP and identify 166 HI sources in the data cubes with HI masses in the range of 107-1010.5M_{sun}_. Our Ursa Major HI catalogue includes 10 first-time detections in the 21-cm emission line. We identify optical counterparts for 165 HI sources (99%). For 54 HI sources (~33%) we find numerous optical counterparts in the HIJASS beam, indicating a high density of galaxies and likely tidal interactions. Four of these HI systems are discussed in detail. We find only one HI source (1%) without a visible optical counterpart out of the 166 HI detections. Green Bank Telescope (FWHM 9-arcmin) follow-up observations confirmed this HI source and its HI properties. The nature of this detection is discussed and compared to similar sources in other HI surveys.
368. HI survey of AGNs
- ID:
- ivo://CDS.VizieR/J/ApJS/177/103
- Title:
- HI survey of AGNs
- Short Name:
- J/ApJS/177/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a new Arecibo survey for HI emission for 113 galaxies with broad-line (type 1) active galactic nuclei (AGNs) out to recession velocities as high as ~35000km/s. The primary aim of the study is to obtain sensitive HI spectra for a well-defined, uniformly selected sample of active galaxies that have estimates of their black hole masses in order to investigate correlations between HI properties and the characteristics of the AGNs. HI emission was detected in 66 out of the 101 (65%) objects with spectra uncorrupted by radio frequency interference, among which 45 (68%) have line profiles with adequate signal-to-noise ratio and sufficiently reliable inclination corrections to yield robust deprojected rotational velocities. This paper presents the basic survey products, including an atlas of HI spectra, measurements of HI flux, line width, profile asymmetry, optical images, optical spectroscopic parameters, as well as a summary of a number of derived properties pertaining to the host galaxies. To enlarge our primary sample, we also assemble all previously published HI measurements of type 1 AGNs for which we can estimate black hole masses, which total an additional 53 objects. The final comprehensive compilation of 154 broad-line active galaxies, by far the largest sample ever studied, forms the basis of our companion paper, which uses the HI database to explore a number of properties of the AGN host galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/430/1309
- Title:
- H_2_O masers in AFGL 2591 VLA 3-N
- Short Name:
- J/MNRAS/430/1309
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we analyse multi-epoch very long baseline interferometry water maser observations carried out with the Very Long Baseline Array towards the high-mass star-forming region AFGL 2591. We detected maser emission associated with the radio continuum sources VLA 2 and VLA 3. In addition, a water maser cluster, VLA 3-N, was detected ~0.5arcsec north of VLA 3. We concentrate the discussion of this paper on the spatio-kinematical distribution of the water masers towards VLA 3-N. The water maser emission towards the region VLA 3-N shows two bow-shock-like structures, northern and southern, separated from each other by ~100mas (~330AU). The spatial distribution and kinematics of the water masers in this cluster have persisted over a time span of 7yr. The northern bow shock has a somewhat irregular morphology, while the southern one has a remarkably smooth morphology. We measured the proper motions of 33 water maser features, which have an average proper motion velocity of ~1.3mas/yr (~20km/s). The morphology and the proper motions of this cluster of water masers show systematic expanding motions that could imply one or two different centres of star formation activity. We made a detailed model for the southern structure, proposing two different kinematic models to explain the three-dimensional spatio-kinematical distribution of the water masers: (1) a static central source driving the two bow-shock structures and (2) two independent driving sources, one of them exciting the northern bow-shock structure, and the other one, a young runaway star moving in the local molecular medium exciting and moulding the remarkably smoother southern bow-shock structure. Future observations will be necessary to discriminate between the two scenarios, in particular by identifying the still unseen driving source(s).
- ID:
- ivo://CDS.VizieR/J/ApJ/473/713
- Title:
- Host galaxies of powerful radio sources
- Short Name:
- J/ApJ/473/713
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper describes those properties of the host galaxies of powerful radio sources that are unique to radio galaxies. The radio galaxies have redshifts up to z=0.5 and radio powers, P(408MHz), ranging from 10^25^ to 10^28^W.Hz^-1^ (H_0_=50km.s^-1^.Mpc^-1^ and q_0_=0). We find that the magnitudes, colors, and surface brightness profiles of these radio galaxies are very diverse. Their rest frame V magnitudes range from -24th to -20th magnitude and are 0.55+/-0.06mag fainter than those of brightest cluster members. Their (B-V) colors can be as red as those of brightest cluster members but may also be ~1 mag bluer. The optical structure of the low-redshift (0.03<z<0.25) radio galaxies may vary ranging from cD to N galaxy behaviour. Although the host galaxies of the low-redshift radio sources are generally "elliptical-like" galaxies, a comparison of the overall structure of radio galaxies to those of radio- quiet "generalized elliptical galaxies" of Schombert shows that only 17% are genuine elliptical galaxies, 9% have elliptical profiles with truncated halos, 26% are roughly elliptical but have disturbed surface brightness profiles, 16% are cD or D galaxies, 7% have double nuclei, and 21% are N galaxies. The only property that radio galaxies, as a class, have in common is that their sizes are relatively larger than those of normal elliptical galaxies of the same absolute magnitude. At the 22d isophote (in V) radio galaxies are 11% larger, at the 24th isophote they are 15% larger, and at the 25th isophote they are 20% larger. The host galaxies of the low-redshift (0.03<z<0.25) FR I and FR II sources have different properties. 69% of all FR I's are associated with cD-like or double nucleus galaxies, 19% with smooth ellipticals, and 13% with disturbed ellipticals; no FR I's are associated with N galaxies. 41% of all FR IIs are associated with N galaxies, 26% with smooth ellipticals, and 26% with disturbed ellipticals; no FR II's are associated with cD-like galaxies. The colors and color gradients are also different, with the FR II's having both bluer colors and a larger dispersion in their color gradients. Powerful FR I and FR II sources exhibit differing cosmological evolutions in their number counts. At low redshifts, almost all powerful sources are FR I's, and at high redshifts they are predominantly FR II's. We suggest that powerful FR I's prefer host galaxies that are the dominant central galaxies of relaxed groups and clusters, while FR II's are most often associated with violent galaxy encounters.
